An alternative to hardware audiometers are software audiometers, which are available in many different configurations.
Screening PC-based audiometer These use a standard computer and can be run by anybody in their home to test their hearing, although their accuracy is not as high due to lack of a standard for calibration. Some of these audiometers are even available on a handheld Windows driven device.
Clinical PC-based audiometer These are generally more expensive than hardware audiometers, but are much more accurate and efficient. They are most commonly used in hospitals, upper-class audiology centers and research communities. Because these audiometers can be calibrated to 1/10 of a dB, calibration is more accurate than hardware audiometers. Some audiometers even provide you with a software developer's kit that provides researchers with the capability to create their own diagnostic tests.